Cadmar was an Aquan male, native to the planet Argo. He was one of three members who sat on the Ruling Tribunal of the Aquans, and held the position of Senior Tribune.

In 2269, a chance encounter with the USS Enterprise led to Cadmar and the council declared it would pass new laws. asserting the need for a continuation of contact with the surface Aquans. (TAS: "The Ambergris Element")